Erlangen 2018 – wissenschaftliches Programm
MO 2.3: Vortrag
Montag, 5. März 2018, 11:00–11:15, PA 1.150
Photorelaxation of Uracil in Explicit Biological Environments — •Sebastian Reiter, Daniel Keefer, and Regina de Vivie-Riedle — Department of Chemistry, LMU Munich
Ultraviolet radiation can trigger photochemical reactions in nucleic acids that might result in damage to the genetic code. Such processes are however largely prevented by the intrinsic property of the five canonical nucleobases to dissipate the absorbed energy via ultrafast, non-radiative relaxation pathways. So far, these processes have been investigated mostly on isolated nucleobases in the gas phase. In this context, recent studies elucidate the relaxation process of uracil after optical excitation to the bright S2 state (ππ*) with femtosecond laser pulses [1, 2]. In our present theoretical work, we go beyond gas phase simulations and investigate uracil in its native RNA environment, where the sugar-phosphate backbone and neighboring nucleobases as well as solvent molecules might influence the relaxation pathway. For this purpose, we employ an approach that combines wave packet dynamics with molecular dynamics  to study the ultrafast population decay from the S2 excited state through a conical intersection to S1, while explicitly taking environmental effects into account. We present our multiscale methodology and discuss the influence of different combinations of neighboring nucleobases and surrounding water molecules on the photostability of uracil.
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